Microwave imaging device

BACKGROUND

The inventive concepts disclosed herein relate generally to the field of image processing, and more specifically to a microwave image processing system ideally operating in the frequency range from 300 MHz to 300 GHz.

Microwave imaging is a field of research that attempts to solve the inverse scattering problem. When radio frequency (RF) energy moves through air and impinges on an object, scattering from the object occurs as the RF energy hits the surface and moves through the object. The idea of the inverse scattering problem is to measure this scattering field and, combined with other information about the object, determine an “image” of the object that created the measured scattered field. Microwave imaging has been used for imaging objects such as, for example, the entire, or parts of, the human body.

SUMMARY OF THE INVENTION

According to one embodiment there is provided a microwave (MW) system. The MW system comprises: an object support adapted to support an object; a MW transmitter configured to transmit a MW towards the object; a MW receiver configured to detect a MW scattered field received from the object; an outer rotation unit having a center axis, the outer rotation unit comprises an outer ring, having a ring shape, with an outer ring mount, upon which one of either an antenna of the MW transmitter or an antenna of the MW receiver is mounted; an inner rotation unit, the inner rotation unit comprises an inner ring, having a ring shape, with an inner ring mount, upon which the other of an antenna of the MW transmitter or an antenna of the MW receiver is mounted, the inner ring being concentric to and having a different radius than the outer ring; a controller configured to independently control both the rotation of the inner ring and the outer ring; and a computation processor configured to receive data including MW data representative of the MW scattered field detected by the MW receiver.

According to an aspect, the outer rotation unit further comprises: an outer ring gear fixed to the outer ring; an outer ring pinion gear engaged with the outer ring gear; and a first motor arranged to drive, via a first shaft, the outer ring pinion gear engaged with the outer ring gear such that the outer ring rotates about the center axis.

According to an aspect, the inner rotation unit further comprises: an inner ring gear fixed to the inner ring; an inner ring pinion gear engaged with the inner ring gear; and a second motor arranged to drive, via a second shaft, the inner ring pinion gear engaged with the inner ring gear such that the inner ring rotates about the center axis.

According to an aspect, the system further comprises: a z-axis actuator configured to drive the object support in the vertical direction.

According to an aspect, the system further comprises a first cable arranged to transmit a MW signal from a MW signal generator or vector network analyzer to an antenna of the MW transmitter; and a second cable arranged to transmit a MW signal from an antenna of the MW receiver to a vector network analyzer or oscilloscope.

According to an aspect, the system further comprises a first slip ring supporting the first cable, and arranged to prevent the first cable from wrapping around, and a second slip ring supporting the second cable, and arranged to prevent the second cable from wrapping around.

According to an aspect, the system further comprises a feedback monitor arranged to measure the rotation of at least one of the inner ring or the outer ring and communicate with the controller to adjust the rotation if a mismatch is determined.

According to an aspect, the MW transmitter comprises a plurality of MW transmitter antennas, and the MW receiver comprises a plurality of MW receiver antennas.

According to an aspect, the controller is further configured to control the vertical direction of the object support using the z-axis actuator.

According to an aspect, the computation processor is further configured to reconstruct a dielectric image of the object from the MW data.

According to an aspect, the system further comprises: an object surface position sensor configured to measure the position of a surface of the object over three dimensions to provide object surface position data; a z-axis actuator configured to drive the object support in the vertical direction; wherein the object surface position sensor is mounted to either the outer ring or inner ring; wherein the controller is further configured to control the vertical direction of the object support via the z-axis actuator.

According to an aspect, the computation processor is further configured to receive object surface position data provided by the object surface position sensor and process object surface position data.

According to an aspect, the processed object surface position data comprises smoothed and resampled object surface position data.

According to an aspect, the object surface position sensor comprises: a radiation source; and a photodetector.

According to an aspect, the computation processor is further configured to reconstruct a dielectric image of the object from the MW data and use object surface position data for a seed in the reconstruction.

According to an aspect, the computation processor is remote from at least one of the object surface position sensor, an antenna of the MW transmitter, or an antenna of the MW receiver and comprises at least two centralized processors.

According to an aspect, the computation processor is further configured to reconstruct a dielectric image of the object from the MW data and use at least both of (1) object surface position data and (2) stored data of a prior microwave image reconstruction which closely matches data of the object, to seed the current reconstruction.

According to an aspect, the computation processor is further configured to reconstruct a dielectric image of the object from the MW data and use a seed determined from at least all of (1) comparing scattered fields of current microwave scan to scattered fields of prior microwave scans stored in a database, (2) comparing processed object surface position data of the current microwave scan to prior processed object surface position data stored in a database, and (3) associating scattered fields of prior microwave scans to reconstructed dielectric images of prior microwave scans stored in a database based on said comparisons.

According to an aspect, the computation processor is further configured to convert a reconstructed dielectric image represented in dielectric values to an image represented in Hounsfield units.

According to another embodiment there is provided a method for producing microwave (MW) images. The method comprises: transmitting a MW from a MW transmitter towards an object; detecting, with a MW receiver, a MW scattered field received from the object; controlling a rotation of the MW transmitter and the MW receiver about a center axis; measuring, with an object position sensor, the position of a surface of the object over three dimensions to form object surface position data; controlling a rotation of the object position sensor about a center axis; controlling a vertical direction of the object; determining a seed for reconstruction of an image based in part on the object surface position data, the seed having a surface coinciding with the object surface position data, and based on stored data of a prior microwave image reconstruction which closely matches data of the object. reconstructing an image of the object using the seed and MW data representative of the MW scattered field detected by the MW receiver.

According to an aspect, the method further comprises converting the reconstructed dielectric image represented in dielectric values to an image represented in Hounsfield units.

According to an aspect, the method further comprises processing the object surface position data through the use of smoothing and resampling to provide processed object surface position data.

According to another embodiment there is provided a MW system. The system comprises: an object support adapted to support an object; a MW transmitter configured to transmit a MW towards the object; a MW receiver configured to detect a MW scattered field received from the object; a first antenna mount having both of (1) a lower mount and (2) a radial translation unit having a translation stage upon which one of either an antenna of the MW transmitter or an antenna of the MW receiver is mounted; a second antenna mount having both of (1) a lower mount and (2) a radial translation unit having a translation stage upon which the other of an antenna of the MW transmitter or an antenna of the MW receiver is mounted; a controller configured to control the radial translation stages to translate radially to and from a center axis; and a computation processor configured to receive data including MW data representative of the MW scattered field detected by the MW receiver.

According to an aspect, each of the radial translation units comprise: a gear engaging a respective translation stage; and a motor driving the gear to drive the respective translation stage.

According to another embodiment there is provided a MW system. The MW system comprises: an object support adapted to support an object; a MW transmitter configured to transmit a MW towards the object; a MW receiver configured to detect a MW scattered field received from the object; a controller programmed to include a control module to control the position of an antenna of the MW transmitter, an antenna of the MW receiver, and the object support; a computation processor configured to receive data including MW data representative of the MW scattered field detected by the MW receiver; wherein the control module comprises: providing a user an interface to input conditions for data collection, the conditions including positions of an antenna of the MW transmitter, an antenna of the MW receiver, and of the object support during data collection and names and locations of the to be collected data for storage; and allowing for data including MW data representative of the MW scattered field detected by the MW receiver to be automatically collected and stored based on user input conditions input by the user.

According to an aspect, the control module further comprises: retrieving at least one of (1) previously taken calibration data and (2) instrument parameters, wherein the MW data is automatically collected based in part on the retrieved previously taken calibration data and/or instrument parameters.

According to an aspect, the control module further comprises: allowing for calibration of initial positions of an antenna of the MW transmitter and an antenna of the MW receiver.

BRIEF DESCRIPTION OF THE DRAWINGS

<figref idref="DRAWINGS">FIG. 1A</figref> is a schematic illustrating a microwave imaging system according to an embodiment of the inventive concepts disclosed herein.

<figref idref="DRAWINGS">FIG. 1B</figref> is a schematic illustrating an object surface position sensor of the microwave imaging system of <figref idref="DRAWINGS">FIG. 1A</figref>.

<figref idref="DRAWINGS">FIG. 1C</figref> illustrates a three-dimensional surface of an object.

<figref idref="DRAWINGS">FIG. 2</figref> is a perspective view of a rotation and support system of a microwave imaging system according to an embodiment of the inventive concepts disclosed herein.

<figref idref="DRAWINGS">FIG. 3</figref> is a side cross-sectional view of a portion of the rotation and support system of <figref idref="DRAWINGS">FIG. 2</figref>.

<figref idref="DRAWINGS">FIG. 4</figref> is a flowchart of exemplary steps used for reconstructing a MW image of an object according to an embodiment of the inventive concepts disclosed herein.

<figref idref="DRAWINGS">FIG. 5</figref> illustrates a control module, including a plurality of submodules, for automating the data collection according to an embodiment of the inventive concepts disclosed herein.

<figref idref="DRAWINGS">FIG. 6A</figref> is a side view of an antenna mount with a radial translation unit according to an embodiment of the inventive concepts disclosed herein.

<figref idref="DRAWINGS">FIG. 6B</figref> is a top view of two antenna mounts according to <figref idref="DRAWINGS">FIG. 6A</figref> mounted on the inner and outer rings, respectively.

<figref idref="DRAWINGS">FIG. 7</figref> is a flow chart of steps for processing obtained object surface position data of an object for later use with reconstructing a MW image according to an embodiment of the inventive concepts disclosed herein.

DETAILED DESCRIPTION

Modeling of RF scattering problems on the scale of the human body is a very computationally intensive task. Solving the inverse scattering problem requires not only solving the forward scattering problem but then using additional computationally intensive algorithms to complete the solution for solving the inverse problem (i.e., create an image). As a result, the overall solution to MWI (microwave imaging), and reconstructing a microwave image of an object based on microwave data including the MW scattered fields of the object, is a computationally heavy and expensive endeavor. A microwave image is usually an image represented in dielectric values consisting of the permittivity and conductivity.

Techniques for MW reconstruction are provided in, for example, U.S. application Ser. No. 13/798,428, entitled “DISTRIBUTED MICROWAVE IMAGE PROCESSING SYSTEM,” filed Mar. 13, 2013, which is incorporated herein by reference in its entirety for devices, methods and techniques related to microwave imaging. Background on microwave imaging is set forth in the following texts: Matteo Pastorino, “Microwave Imaging,” WILEY, 2010; Jaleel Akhtar, “Microwave Imaging: Reconstruction of One Dimensional Permittivity Profiles,” VDM Verlag, 2008; and Bindu Gopinathan Nair, “Active Microwave Imaging for Mammography: Microwave Medical Imaging,” Lap Lambert Academic Publishing, 2012.

Algorithms for reconstructing a microwave image can be iterative or not iterative. In iterative algorithms, the number of iterations may be reduced by providing a good initial estimate, or seed, of the object being imaged. The seed is an initial estimate of the electrical properties of the subject object. For example, if the object being imaged is a human body of a patient, prior MW scan data including a prior microwave image reconstruction of a similar patient may be used as the seed, where the patient and the similar patient are similar in sex, age, weight and/or location of scanned data as described in U.S. application Ser. No. 13/798,428, entitled “DISTRIBUTED MICROWAVE IMAGE PROCESSING SYSTEM,” filed Mar. 13, 2013, which is incorporated by reference in its entirety for devices, methods and techniques related to microwave imaging. Even in non-iterative reconstruction algorithms reducing computational demands can be achieved using knowledge of the surface of the object.

The present inventors have realized that the seed may be further enhanced based on the position of the surface of the object being imaged. Thus, the position of the surface of the object may be measured in three dimensions, and that surface position data used to enhance the initial seed.

Microwave Imaging System

<figref idref="DRAWINGS">FIG. 1A</figref> is a schematic of a microwave imaging system <b>100</b> according to the inventive concepts disclosed herein. The system <b>100</b> includes a MW transmitter antenna <b>10</b> configured to emit MW radiation, and a MW receiver <b>20</b> antenna configured to detect MW scattered fields from the object. One of the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> is mounted on one of an outer rotation unit <b>30</b> and an inner rotation unit <b>40</b>, while the other of the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> is mounted on the other of the outer rotation unit <b>30</b> and the inner rotation unit <b>40</b>. Thus, each of the outer rotation unit <b>30</b> and the inner rotation unit <b>40</b> has one of the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> mounted thereon.

The MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> may be any MW antennas appropriate for microwave imaging. For example, for biomedical imaging, an appropriate antenna to operate over ultra-wideband frequencies is described in U.S. application Ser. No. 14/054,105 entitled “ANITPODAL VIVALDI ANTENNA ARRAY FOR BIOMEDICAL IMAGING,” filed Oct. 15, 2013, incorporated herein in its entirety for devices, methods and techniques related to microwave imaging. The MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> may comprise any antenna including an antipodal Vivaldi antenna. In certain embodiments the antennas used may be patch antennas, multi-band antennas, or monopole antennas. The size of the antennas will vary depending upon the application.

The microwave imaging system <b>100</b> may further have a controller <b>50</b>. The controller <b>50</b> is configured to control the outer rotation unit <b>30</b> and the inner rotation unit <b>40</b> so that the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> may be rotated about a center axis <b>60</b>, which points out of the page in the z-direction in <figref idref="DRAWINGS">FIG. 1A</figref>. Each of the outer rotation unit <b>30</b> and the inner rotation unit <b>40</b> allows for rotation of a respective of the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> from 0° to 360° about the center axis <b>60</b>. The controller <b>50</b> may further be configured to control the MW transmitter antenna <b>10</b> to cause the MW transmitter antenna <b>10</b> to emit MW radiation, and to control the MW receiver antenna <b>20</b> to detect a MW scattered field, and further to collect MW data from the MW receiver antenna <b>20</b>. In some embodiments, the center axis <b>60</b> may be pointed in the x or y directions in <figref idref="DRAWINGS">FIG. 1A</figref>.

The microwave imaging system <b>100</b> may have an object mount <b>70</b>, upon which an object is mounted. The object mount <b>70</b> may be moved along the center axis <b>60</b> direction, i.e., along the z-axis. In some embodiments, the object may be placed in a tank with an open enclosure filled with a matching medium or liquid. The tank that the object is placed in is then mounted to the object mount <b>70</b>. In some embodiments the object mount <b>70</b> may instead be moved along the x-axis or y-axis.

The controller <b>50</b> may include subcontrollers <b>50</b><i>a </i>and <b>50</b><i>b</i>. The subcontroller <b>50</b><i>a </i>may be configured to control the outer rotation unit <b>30</b> and the inner rotation unit <b>40</b> so that the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> may be rotated about the center axis <b>60</b>. The subcontroller <b>50</b><i>b </i>may be configured to control the MW transmitter antenna <b>10</b> to cause the MW transmitter antenna <b>10</b> to emit MW radiation, and to control the MW receiver antenna <b>20</b> to detect MW scattered fields, and further to collect MW data from the MW receiver antenna <b>20</b>. The controller <b>50</b> provides for collection of data by changing the positions of the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> by rotation of the outer rotation unit <b>30</b> and the inner rotation unit <b>40</b>, and collecting data at each of the positions. The positions may be changed in stepwise manner, for example, and data collected at each step.

The subcontroller <b>50</b><i>a </i>may comprise a processor <b>54</b><i>a </i>and memory <b>58</b><i>a</i>, so as to allow the subcontroller <b>50</b><i>a </i>to perform its control functions. The subcontroller <b>50</b><i>a </i>may be hardwired and/or may contain software and programs to allow the subcontroller <b>50</b><i>a </i>to perform its control functions. Similarly, the subcontroller <b>50</b><i>b </i>may comprise a processor <b>54</b><i>b </i>and memory <b>58</b><i>b</i>, so as to allow the subcontroller <b>50</b><i>b </i>to perform its control functions. The subcontroller <b>50</b><i>b </i>may be hardwired and/or may contain software and programs to allow the subcontroller <b>50</b><i>b </i>to perform its control functions.

Alternatively, the controller <b>50</b> need not include subcontrollers to perform its control functions, or may include more than two subcontrollers. Each of the subcontrollers may control one or more functions of the controller <b>50</b>. The functions of the subcontrollers may include controlling, in addition to changing the positions of the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> by rotating the outer rotation unit <b>30</b> and the inner rotation unit <b>40</b>, changing the positions of the object surface position sensor <b>80</b> by rotating the outer rotation unit <b>30</b> or the inner rotation unit <b>40</b>, discussed further below, controlling the object mount <b>70</b> to move along the center axis <b>60</b> direction, i.e., along the z-axis, and to control radial movement to and from the center axis <b>60</b> in some embodiments. In some embodiments, the subcontrollers may include controlling the object mount <b>70</b> to move along the x-axis or y-axis.

The outer rotation unit <b>30</b> and the inner rotation unit <b>40</b> may be independently rotated so that the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> are independently rotated about the center axis <b>60</b> of the outer rotation unit <b>30</b> and the inner rotation unit <b>40</b>. As seen in <figref idref="DRAWINGS">FIG. 1A</figref>, the MW transmitter antenna <b>10</b> is at an angular position about center axis <b>60</b> corresponding to an angle β with respect to the y-axis, which is vertical in <figref idref="DRAWINGS">FIG. 1A</figref>. Similarly, the MW receiver antenna <b>20</b> is at an angular position about center axis <b>60</b> corresponding to an angle α with respect to the y-axis. The angles α and β may be independently varied based on the rotations of the outer rotation unit <b>30</b> and the inner rotation unit <b>40</b>, respectively. Thus, measurements using the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> may be taken for any pair of angles α and β, and for a particular position along the z-axis. Thus, two rotation units are used to provide a full range of pairs of angles, and the object mount <b>70</b> provides for movement along the z-axis. The position of the object <b>5</b> relative to the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> may be described in Cartesian or spherical coordinates.

As illustrated in <figref idref="DRAWINGS">FIGS. 1A and 1B</figref>, the microwave imaging system <b>100</b> may have an object surface position sensor <b>80</b> configured to measure the surface position of the object <b>5</b>. The object surface position sensor <b>80</b> measures the position of the surface of the object in three dimensional space. The object surface position sensor <b>80</b> provides a narrow illumination beam <b>82</b> which illuminates the object, and receives a reflection beam <b>84</b> back from the object based on the illumination beam <b>82</b>. Alternatively, the object surface position sensor <b>80</b> may receive a reflection beam <b>84</b> without providing any illumination beam <b>82</b> to illuminate the object. The object surface position sensor <b>80</b> can make use of the following equation: 2 d=c₀t, where d is the distance from object surface position sensor <b>80</b> to a point on the object, c₀is the wave speed in air, and t is the time delay. The object surface position sensor <b>80</b> measures the distance between the sensor and the object for multiple angular positions to form a contour line. This contour line can be in polar coordinates. A contour line is collected for multiple z-axis positions of the object i.e. the object mount <b>70</b> is vertically translated along the center axis <b>60</b> direction. In some embodiments, the contour line is collected for multiple x-axis or y-axis positions of the object i.e. the object mount <b>70</b> is horizontally translated along the center axis <b>60</b> direction.

<figref idref="DRAWINGS">FIG. 1C</figref> illustrates a surface in three dimensions of the object <b>5</b>, where three points of the object in Cartesian coordinates are shown. While three points of the surface <b>5</b> are shown for ease of illustration in <figref idref="DRAWINGS">FIG. 1C</figref>, in practice the object surface position sensor <b>80</b> will measure the position of many more points of the surface of the object <b>5</b> in a three dimensional space. In an embodiment, once the object surface position in three dimensions is obtained, such as by the object surface position sensor <b>80</b>, the resulting coordinates obtained are averaged, smoothed, and resampled, or otherwise processed, to form the object surface that is used in practice. Thus, the object surface position data obtained by the sensor <b>80</b> may be processed as desired prior to further use.

The object may be moved relative to the sensing beam <b>82</b> to provide for a detection of the position of substantially the entire surface of the object. For example, the object may be vertically translated and rotated about the center axis <b>60</b> relative to the sensing beam <b>82</b>. To achieve the relative motion, the object may be vertically translated via the object mount <b>70</b>, and the surface position sensor <b>80</b> may be mounted on the outer rotation unit <b>30</b> or the inner rotation unit <b>40</b> so as to rotate the surface position sensor <b>80</b> about the center axis <b>60</b>. To collect the full surface of the object the object surface position sensor mounted on one of the rotation units is progressively rotated from 0° to 360° about the center axis <b>60</b>. As an alternative to achieve relative rotation, the object mount <b>70</b> may be rotated about the center axis <b>60</b>. In one embodiment, the object surface position data is obtained by progressively rotating from 0 to 360° the surface position sensor <b>80</b> mounted on one of the rotation units for a series of consecutive object mount <b>70</b> positions.

The surface position sensor <b>80</b> may comprise an IR sensor which radiates and detects IR radiation from the surface of the object via a photodetector <b>88</b>. Alternatively, the surface position sensor <b>80</b> may include a radiation source <b>86</b>, such as a laser or light emitting diode, to provide the sensing beam <b>82</b>, and the photodetector <b>88</b> to detect the reflection beam <b>84</b>. The surface position sensor <b>80</b> may comprise a photographic device, such as a camera.

The system <b>100</b> may include a computation processor <b>90</b> which receives data including MW data representative of the MW scattered field from the controller <b>50</b> and which receives the object surface position data from controller <b>50</b>, and performs MW image reconstruction of the object based on the MW data, object surface position data, and data from database <b>95</b>. The data in database <b>95</b> may be prior collected MW data including MW incident fields, MW scattered fields, object surface position data, and reconstructed dielectric images. The computational processor <b>90</b> may comprise one or more subprocessors. The computational processor <b>90</b> is not just limited to one processor and may contain at least two processors which employ parallel computing techniques. In addition, the computation processor <b>90</b> may comprise both central processing units and graphics processing units. In one embodiment, the two processors are employed in two high performance computers networked together using Infiniband® network cards. Alternatively, the computational processor <b>90</b> may transmit and receive data including MW scattered fields and object position data to and from a remote centralized processor and remote database. Remote as used herein can mean in a different room or different building in addition to meaning many miles away. The computation processor <b>90</b> may be remote from the object surface position sensor <b>80</b>, the MW transmitter antenna <b>10</b>, and the MW receiver antenna <b>20</b>.

Rotation and Support System

<figref idref="DRAWINGS">FIGS. 2 and 3</figref> illustrate a rotation and support system <b>200</b> for the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> for the microwave imaging system <b>100</b> according to an embodiment of the invention.

The rotation and support system <b>200</b> includes a support <b>202</b> which includes a support surface mount <b>207</b>, and a rotation surface mount <b>203</b>. The rotation surface mount <b>203</b> includes an inner ring support region <b>204</b> and an outer ring support region <b>206</b>. The inner ring support region <b>204</b> supports an inner ring <b>210</b>, while the outer ring support region <b>206</b> supports an outer ring <b>220</b>.

The inner ring <b>210</b> has an inner ring mount <b>212</b>, an inner gear ring <b>214</b> with inner gear ring teeth <b>216</b> and a spacer <b>218</b> between the inner ring mount <b>212</b> and the inner gear ring <b>214</b>. A bottom surface of the inner ring mount <b>212</b> is supported by a top surface of inner ring support region <b>204</b>, which may be in the form of a lip, on the inner ring support region <b>204</b>. The region of contact between the inner ring support region <b>204</b> and the inner ring mount <b>212</b> may include a friction reducing substance to reduce the friction between the inner ring support region <b>204</b> and the inner ring mount <b>212</b> when the inner ring <b>210</b> is rotating relative to the support <b>202</b>.

The outer ring <b>220</b> has an outer ring mount <b>222</b>, and an outer gear ring <b>224</b> with outer gear ring teeth <b>226</b>. A bottom surface of the outer ring mount <b>222</b> is supported by a top surface of outer ring support region <b>206</b>. The region of contact between the outer ring mount <b>222</b> and the outer ring support region <b>206</b> may include a friction reducing substance to reduce the friction between outer ring mount <b>222</b> and the outer ring support region <b>206</b> when the outer ring <b>220</b> is rotating relative to the support <b>202</b>.

The rotation and support system <b>200</b> further includes the object mount <b>70</b>, upon which an object is placed, and a z-axis actuator <b>246</b>. The z-axis actuator <b>246</b> drives the object mount <b>70</b> upward or downward via a drive rod <b>247</b> along the axis <b>60</b> direction, i.e., along the z-axis. The z-axis actuator <b>246</b> may be controlled via the controller <b>50</b> (see <figref idref="DRAWINGS">FIG. 1A</figref>).

The rotation and support system <b>200</b> includes an inner ring pinion gear <b>230</b>, inner ring stepper motor <b>236</b>, which may include an encoder, and inner ring drive shaft <b>238</b> arranged to drive the inner ring <b>210</b> to be rotated. The inner ring pinion gear <b>230</b> may be on a bottom surface of the inner ring support <b>204</b>. The inner gear ring teeth <b>216</b> of the inner gear ring <b>214</b> engage with the inner ring pinion gear <b>230</b>. The inner ring stepper motor <b>236</b> rotates the inner ring drive shaft <b>238</b>, which in turn rotates the inner ring pinion gear <b>230</b>. The rotating inner ring pinion gear <b>230</b>, which is engaged with the inner gear ring teeth <b>216</b> of the inner gear ring <b>214</b>, thus drives the inner ring <b>210</b> about the axis <b>60</b> direction.

The rotation and support system <b>200</b> includes an outer ring pinion gear <b>232</b>, outer ring stepper motor <b>240</b>, which may include an encoder, and outer ring drive shaft <b>242</b> arranged to drive the outer ring <b>220</b>. The outer ring pinion gear <b>232</b> may be on a top surface of the support surface mount <b>207</b>. The outer gear ring teeth <b>226</b> of the outer gear ring <b>224</b> engage with the outer ring pinion gear <b>232</b>. The outer ring stepper motor <b>240</b> rotates the outer ring drive shaft <b>242</b>, which in turn rotates the outer ring pinion gear <b>232</b>. The rotating outer ring pinion gear <b>232</b>, which is engaged with the outer gear ring teeth <b>226</b> of the outer gear ring <b>224</b>, thus drives the outer ring <b>220</b> to be rotated about the axis <b>60</b> direction.

The rotation and support system <b>200</b> includes an inner ring antenna mount <b>260</b> and an outer ring antenna mount <b>262</b>, which are mounted on the inner ring mount <b>212</b> and the outer ring mount <b>222</b>, respectively. The inner ring antenna mount <b>260</b> and outer ring antenna mount <b>262</b> may be removed from the inner ring mount <b>212</b> and outer ring mount <b>222</b>. One of the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> is mounted on one of the inner ring antenna mount <b>260</b> and the outer ring antenna mount <b>262</b>, while the other of the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> is mounted on the other of the inner ring antenna mount <b>260</b> and the outer ring antenna mount <b>262</b>. Thus, each of the inner ring <b>210</b> and the outer ring <b>220</b> has one of the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> mounted thereon. Different size inner ring antenna mounts <b>260</b> and outer ring antenna mounts <b>262</b> can be used to allow for different sizes of MW transmitter <b>10</b> and MW receiver antenna <b>20</b> to be used. This is helpful because antennas designed for different frequency ranges come in different sizes.

The inner ring <b>210</b> and the outer ring <b>220</b> may be independently rotated via the inner ring stepper motor <b>236</b> and the outer ring stepper motor <b>240</b> so that the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> are independently rotated about the center axis <b>60</b>. Thus, measurements using the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> may be taken for any pair of angles α and β, as discussed with respect to <figref idref="DRAWINGS">FIG. 1A</figref> above.

Further, the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> may comprise a single MW receiver antenna, and a single MW transmitter antenna. By using only a single MW receiver antenna, and a single MW transmitter antenna, interference of extra antennas with the radiation from the object being investigated may be reduced. In an embodiment, it is also possible to use multiple MW transmitter antennas <b>10</b> and the MW receiver antennas <b>20</b> which would necessitate the use of multiple inner ring antenna mounts <b>260</b> and outer ring antenna mounts <b>262</b>.

The MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> may respectively have cables <b>248</b> and <b>250</b> to conduct MW radiation to or from the antennas. The cables <b>248</b> and <b>250</b> may be respectively connected to slip rings <b>253</b> and <b>254</b>. The slip rings <b>253</b> and <b>254</b> allow that the cables <b>248</b> and <b>250</b> will not wrap around as the inner ring <b>210</b> and the outer ring <b>220</b> are rotated about the center axis <b>60</b>. The cables <b>248</b> and <b>250</b> may connect to the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b>, respectively, via SMA connectors. Cables <b>248</b>′ and <b>250</b>′ connect to slip rings <b>253</b> and <b>254</b>, respectively, and may further connect to a vector network analyzer, arbitrary waveform generator, and/or oscilloscope (not shown). When using an arbitrary waveform generator and oscilloscope, cable <b>248</b>′ is connected to the oscilloscope, and cable <b>250</b>′ is connected to the arbitrary waveform generator.

The microwave imaging system <b>100</b> may further include a feedback monitor <b>266</b> that measures the rotation of the rings <b>210</b> and <b>220</b> so as to allow for a closed loop system, where the rotation of the rings <b>210</b> and <b>220</b> is not only driven, but is measured to allow for correction based on feedback from the feedback monitor <b>266</b>. The feedback monitor <b>266</b> may count outer gear ring teeth <b>226</b> of the outer gear ring <b>224</b> and the inner gear ring teeth <b>216</b> of the inner gear ring <b>214</b> to measure the rotation of the rings <b>210</b> and <b>220</b>. There are situations where it is possible for the subcontroller to change the positions of the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> by rotating the rings <b>210</b> and <b>220</b> but where the rotation thought to occur by the subcontroller is different than that measured by the feedback monitor <b>266</b>. In this situation the feedback monitor <b>266</b> would communicate with the subcontroller to ensure the rotation is correct.

The microwave imaging system <b>100</b> may further include the object surface position sensor <b>80</b> as discussed above with respect to <figref idref="DRAWINGS">FIG. 1</figref>. The object surface position sensor <b>80</b> may be mounted on the support surface <b>207</b> of the support <b>202</b>. In one embodiment, the rotation and support system <b>200</b> includes an object position sensor mount <b>272</b> which may be mounted on the outer ring mount <b>222</b>. The object surface position sensor <b>80</b> is mounted on the object position sensor mount <b>272</b>. The object position sensor mount <b>272</b> may be removed from outer ring mount <b>222</b>.

The inner rotation unit <b>40</b> of <figref idref="DRAWINGS">FIG. 1A</figref> includes the inner ring <b>210</b>, inner ring mount <b>212</b>, inner gear ring <b>214</b>, spacer <b>218</b>, inner ring pinion gear <b>230</b>, inner ring stepper motor <b>236</b> and inner ring drive shaft <b>238</b>. The outer rotation unit <b>30</b> of <figref idref="DRAWINGS">FIG. 1A</figref> includes the outer ring <b>220</b>, outer ring mount <b>222</b>, outer gear ring <b>224</b>, outer ring pinion gear <b>232</b>, outer ring stepper motor <b>240</b> and outer ring drive shaft <b>242</b>.

<figref idref="DRAWINGS">FIGS. 6A and 6B</figref> illustrate an embodiment where the antenna mounts <b>260</b> and <b>262</b> each include a lower mount and a radial translation unit. Specifically, the antenna mounts <b>260</b> and <b>262</b> each includes a lower mount <b>274</b> and a radial translation unit <b>278</b>. The radial translation unit <b>278</b> includes a translation stage <b>282</b>, a gear <b>286</b> and a motor <b>290</b>.

In operation, the motor <b>290</b> is controlled by the controller <b>50</b> so as to rotate the gear <b>286</b>, which is engaged with teeth of the translation stage <b>282</b>. Thus, the translation stage <b>282</b>, which supports one of the MW receiver antenna <b>20</b> or the MW transmitter antenna <b>10</b>, is controlled to translate the antenna along the axial direction to or from the center axis <b>60</b>.

The radial translation unit <b>278</b> allows for more flexibility in positioning the MW receiver antenna <b>20</b> or the MW transmitter antenna <b>10</b> by including a radial position component. Thus, in this embodiment, the MW receiver antenna <b>20</b> and the MW transmitter antenna <b>10</b> are not restricted to following a circular path around the center axis. Further, the radial translation unit <b>278</b> allows for further flexibility in positioning the MW receiver antenna <b>20</b> and the MW transmitter antenna <b>10</b> relative to the object <b>5</b>. The surface position of the object may be measured by the object surface position sensor <b>80</b>, and then a suitable distance away from the object, such as the closest possible, for the MW receiver antenna <b>20</b> and the MW transmitter antenna <b>10</b> may be set according to the measured surface position. It has been found that some types of signals like evanescent waves attenuate quickly with the distance away from the surface. Hence, it is possible to detect these types of signals using the radial translation unit <b>278</b>. In the embodiment shown in <figref idref="DRAWINGS">FIG. 6B</figref> the MW receiver antenna <b>20</b> and the MW transmitter antenna <b>10</b> are positioned the same distance from the center axis <b>60</b>. This is not possible without the radial translation unit <b>278</b>.

The components of the rotation and support system <b>200</b> in the vicinity of the object mount <b>70</b> and the MW transmitter antenna <b>10</b> and MW receiver antenna <b>20</b> may be made of a non-metallic material so as to reduce interference with the microwaves emitted and detected, at least in the case where component need not be a metallic material to conduct electricity. The non-metallic material may be plastic, or wood, for example. For example, the support <b>202</b>, inner ring <b>210</b>, outer ring <b>220</b>, pinion gears <b>230</b> and <b>232</b>, and drive shafts may all be made of a non-metallic material.

The size and dimensions of the rotation and support system <b>200</b> can be varied to account for different sizes of the object <b>5</b>. In this way a larger object <b>5</b> will necessitate the use of a larger object mount <b>70</b>. This in turn will necessitate the use of a larger inner ring <b>210</b> and outer ring <b>220</b>. While a smaller object <b>5</b> will not require using a smaller object mount <b>70</b> and inner and outer rings, the inner ring <b>210</b> and outer ring <b>220</b> may be made smaller to obtain better image reconstructions. In certain embodiments, the inner ring <b>210</b> and the outer ring <b>220</b> may be of a size to allow a human body (taken as object <b>5</b>), or a part of a human body, such as an arm or a leg, to pass within the inner ring <b>210</b>. Different applications and use cases will require different sized rings.

Reconstruction of Object Image Using Surface Position of Object

<figref idref="DRAWINGS">FIG. 4</figref> is a flow chart of exemplary steps used for reconstructing a MW image of an object, such as body of a patient, from data including using measured MW scattered fields and surface position data of the object.

In step <b>401</b>, MW data including MW scattered fields based on scanning the object is obtained employing measurements using the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> which may be angularly rotated and/or z-axis translated relative to the body during a body scan. In an embodiment, the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> may be angularly rotated, radially translated, and/or vertically translated relative to the body during a body scan.

In step <b>402</b> surface position data of the surface of the object is obtained. The surface position data may be measured using the object surface position sensor <b>80</b>. The surface position data may be processed as desired, in step <b>402</b><i>b</i>, such as by averaging, applying a smoothing operation, and resampling. <figref idref="DRAWINGS">FIG. 7</figref> illustrates steps for processing surface position of the step <b>402</b><i>b. </i>

<figref idref="DRAWINGS">FIG. 7</figref> is a flow chart of exemplary steps used in an embodiment for processing obtained object surface position data of an object, such as a body of a patient, for later use with reconstructing a MW image. In step <b>701</b>, the object surface position sensor <b>80</b> collects radial position and records angular position in polar coordinates to obtain object surface position data. Multiple object surface position data for the same angular position and z-axis position can be collected and then the radial position averaged to form the object surface position data. In step <b>702</b>, for each z-axis position, the angular position collected and radial position is resampled to have angles go from 0 to 360° with a 1° step or some other step. The resampling of the radial position based on the new angles may be done using interpolation. In step <b>703</b>, smoothing or filtering of the new radial positions, for each z-axis position, is performed. For example, in a filtering step, the Fourier Transform of the new radial positions is taken, the high frequency information is set to zero, and the real component of the Inverse Fourier transform of this result is taken. Alternatively, a moving average of the new radial positions is taken to perform smoothing. In step <b>704</b>, after the resampling of the new angles and smoothing step occurs, the data is converted from polar coordinates to Cartesian coordinates for each z-axis position. In step <b>705</b>, additional tweaks and corrections to the obtained resampled and smoothed surface position data in Cartesian coordinates is performed. In some cases, the final contour collected corresponding to the last z-axis position is set to the first contour corresponding to the first z-axis position collected to ensure a full surface position is collected. In some cases, a few contours are ignored such as the top few contours. This is useful such as in some cases there may be errors at the beginning or end of the surface position sensor scan which corresponds to the first few or last few z-axis positions. In step <b>706</b>, the number of z-axis positions collected is resampled to be different than the actual number of z-axis positions collected. The resampling of the z-axis position is done using interpolation and designed to allow for a finer or coarser resolution in the z-axis. Additional smoothing and filtering operations can be performed if desired after resampling. In step <b>707</b>, the X and Y coordinates for each contour can be resampled to allow for a finer or coarser resolution. Additional smoothing and filtering operations can be performed if desired after resampling. In step <b>708</b>, the processed surface position data which can be used for reconstructing a MW image is obtained by converting the xy contours to a binary 3D surface image. Once the contours for each resampled z-axis position is determined they are stacked to form a 3D surface of the object. The 3D surface of the object in X, Y, Z coordinates contains just the contours so only the information corresponding to the surface. To be able to use the 3D surface for use in reconstructing a MW image it is necessary to create a 3D image in pixel values where the pixels on and inside the surface can be distinguished from the pixels outside the surface. The 3D surface of the object X, Y, Z coordinates are converted to pixel values using interpolation or an algorithm to convert each xy contour for each resampled z-axis position into a binary image contained in pixel values where 1 s are inside and include the surface and 0s are outside and exclude the surface or vice versa. A binary 3D image representing the surface of the object is obtained which can be used with reconstructing a MW image.

Referring to <figref idref="DRAWINGS">FIG. 4</figref>, in step <b>403</b> a database of prior data is searched. The database includes prior collected MW scattered fields, prior reconstructed dielectric images, and prior surface position data. Associated with the data in the database are other characteristics that were recorded as part of the original scan. These characteristics include the type, frequency, size, and positional information of the MW receiver(s) and transmitter(s), the geometric parameters of the collection device including the size of the inner and outer rings and size of other components as described in <figref idref="DRAWINGS">FIG. 2</figref> and <figref idref="DRAWINGS">FIG. 3</figref>, calibration data and instrument parameters used during collection, the object classification such as if an animal or human, specific information about the site where the data was collected, demographic information about the patient including sex, age, weight, and height, a reason why the scan was conducted such as any presenting symptoms, and the requested output of the scan including the anatomy and area of interest. The collected MW scattered fields from step <b>401</b> and the collected and/or processed surface position data from step <b>402</b> along with recorded characteristics such as those described above will get saved into the database along with the later reconstructed dielectric image for use with future MW imaging reconstructions.

This search in step <b>403</b> involves looking for prior MW scans that are similar in terms of the MW scattered fields and if available prior surface position data to the current MW scattered field obtained in step <b>401</b> and surface position data obtained in step <b>402</b>. The database is searchable in terms of the MW scattered fields and surface position data and also in other characteristics including patient sex, age, weight, height, and location of the scanned data. In step <b>404</b>, it is determined if there is a possible best or closest match between the current MW scattered field and prior MW scattered field in the database that can be used. There is a computational component in this block that does further feature extraction and comparisons in order to ensure like data is being compared. The possible match determination involves comparing the obtained MW scattered field in step <b>401</b>, the obtained surface position data in step <b>402</b>, and prior data in a database in step <b>403</b>. In an embodiment, the best match is determined in a series of two consecutive steps. In the first step prior patients similar in MW scattered fields, patient sex, age, weight, height, and location of the scanned data are determined. The minimum sum of the distances taken for all of these characteristics may be used to generate a list of potential prior patients. In the second step the current surface position data from step <b>402</b> is compared to the surface position data of the prior patients (from the list of prior patients obtained in the first step). The prior patient that has the surface position data that most closely matches the current surface position data is taken as the best match. In an embodiment, the surface position data of a prior patient may be determined by an edge detection algorithm on the prior reconstructed image obtained in the database. This can be useful when the prior surface position data is missing or absent. In another embodiment, comparison between surface position data of the prior patient to the current patient may be based on minimizing the sum of the distances between the surfaces using imaging processing and optimization techniques.

In step <b>405</b>, if a best match is found, the prior reconstructed dielectric image of the best match is retrieved from the database of prior data. The database of dielectric images is a database of successfully reconstructed dielectric images. In step <b>406</b>, if there is a best match in step <b>404</b>, a seed (initial estimate of the electrical properties of the subject object) is determined based on the prior reconstructed dielectric image retrieved and based on the obtained surface position data from step <b>402</b>. If there is not a best match in step <b>404</b>, the seed is determined based on the obtained surface position data, which may be collected surface position data, which has been processed. The seed is then used to reconstruct a dielectric image, described further below.

The seed has a surface coinciding with the obtained object surface position data or very close. That is, the seed is such that the boundary of the object coincides, or is very close, with the object surface position data. For example, if the object, as determined by the surface position sensor, is a sphere with a radius r, the seed may contain an object of a sphere with a radius r. The dielectric values outside the sphere would be assigned values of the medium surrounding the object. The dielectric values inside the sphere would be assigned values based on prior reconstructed dielectric images retrieved if a best match was found or if a best match not found based on prior knowledge or random values using prior knowledge about the range. In the case when a best match is found, there may be slight mismatch between the object as positioned in the prior reconstructed data and the obtained surface position data, but the obtained surface position data may override the prior position data based on the prior reconstructed data retrieved. Alternatively, when a best match is found, the dielectric values of the seed may allow for a slight mismatch between the obtained surface position data and would be based on changing the shape of the prior reconstructed data to closely match the obtained surface position data. In the case when a best match is not found, the dielectric values inside the obtained surface position data is assigned using prior knowledge about the assumed tissues or materials of the object <b>5</b>. Alternatively, when a best match is not found, the seed is assigned random dielectric values inside the obtained surface position data using prior knowledge about the range of dielectric values for the assumed tissues or materials of the object <b>5</b>.

As discussed above, this is a substantial feature because iterative reconstruction processing takes substantially less time if a better seed (or starting point) is used. The seed depends not only on the prior reconstructed data from a match, but further depends on the obtained surface position data of the object being investigated. Thus, the system provides for a substantially reduced processing time because voxels outside the object do not have to be reconstructed and the “seed” for the volume outside the object can be assumed to be the medium surrounding the object.

In step <b>407</b>, the dielectric images are reconstructed using MWI Reconstruction and Learning Algorithms, for example as described in U.S. application Ser. No. 13/798,428, entitled “DISTRIBUTED MICROWAVE IMAGE PROCESSING SYSTEM,” filed Mar. 13, 2013, which is incorporated by reference in its entirety. In step <b>408</b> (Digital Imaging and Communications in Medicine) DICOM encoding or Hounsfield encoding may be performed on the reconstructed dielectric images, if desired, as described in U.S. application Ser. No. 13/798,428, or U.S. Pat. No. 9,111,334. Step <b>408</b> involves converting the raw dielectric image represented in dielectric values to an image represented in Hounsfield units if performing Hounsfield encoding.

Control Module

<figref idref="DRAWINGS">FIG. 5</figref> illustrates a control module <b>500</b> for automating the data collection from the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b>, automating the data collection from the object surface position sensor <b>80</b>, motor control to control the motors <b>236</b>, <b>240</b>, and <b>290</b>, and actuator control to control the actuator <b>246</b>. The control module may be implemented on the controller <b>50</b> of <figref idref="DRAWINGS">FIG. 1A</figref> as software, firmware or hardware, for example, and may be remote from the site of the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b>.

The control module <b>500</b> may include a number of submodules. For example, the control module may include position calibration submodule <b>510</b>, data file submodule <b>520</b>, rotation parameter submodule <b>530</b>, previous initialization submodule <b>540</b>, interface submodule <b>550</b>, object detection submodule <b>560</b>, MW data collection submodule <b>570</b>, radial parameter submodule <b>580</b>, and vertical parameter submodule <b>590</b>.

The position calibration submodule <b>510</b> allows for calibration of initial positions of various hardware components. The MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> initial positions may be calibrated. This is set through the use of the inner ring stepper motor <b>236</b> rotating the inner ring <b>210</b> and the outer ring stepper motor rotating the outer ring <b>220</b>. In an embodiment, this is also set through the motor <b>290</b> which radially translates the translation stage <b>282</b>. The feedback monitor <b>266</b> may provide feedback on the angular and radial position of the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> relative to the object. Further, the initial z-axis position of the object mount <b>70</b> may be calibrated through the use of the z-axis actuator <b>246</b>. In addition, the object surface position sensor <b>80</b> may be calibrated through the use of the outer ring stepper motor rotating the outer ring <b>220</b>. The purpose of using the position calibration submodule <b>510</b> is to calibrate the initial positions to known positions so that the parameters of rotations and translations saved are meaningful.

In the data file submodule <b>520</b>, the folder and storage locations of the data files to be collected and stored are set and if desired an antenna input file is set and the number of data files to collect at the same angular, radial, and vertical position is set. The storage locations may be remote from the site of the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b>. In an embodiment the antenna input file is a signal which is loaded into an arbitrary waveform generator and sent to the MW transmitter antenna <b>10</b> via cable <b>250</b> which is connected to slip ring <b>254</b>, and cable <b>250</b>′, which is connected to the arbitrary waveform generator.

In the rotation parameter submodule <b>530</b> the minimum and maximum rotation angle and the angular step for the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> or object surface position sensor <b>80</b> are set. The rotation parameter submodule <b>530</b> provides the rotational parameters of the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> for a MW data collection scan. The rotation parameter submodule <b>530</b> also provides the rotational parameters of the object surface position sensor <b>80</b> for an object position sensor data collection scan. This is set through the use of the inner ring stepper motor <b>236</b> rotating the inner ring <b>210</b> and the outer ring stepper motor rotating the outer ring <b>220</b>.

In the radial parameter submodule <b>580</b> the radial position parameters for the position of the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> radially to and from the center axis <b>60</b> are set. Thus, the radial parameter submodule <b>580</b> provides the radial position parameters of the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> for a scan. This is set through the motor <b>290</b> which radially translates the translation stage <b>282</b>.

In the vertical parameter submodule <b>590</b> the vertical position parameters for the position of the object mount <b>70</b> are set. The vertical position parameters of the z-axis position of the object mount <b>70</b> is set through the use of the z-axis actuator <b>246</b>.

In the previous initialization submodule <b>540</b>, previously taken calibration data and/or instrument states is retrieved. In an embodiment if using a vector network analyzer, the file containing a prior calibration is loaded. If smoothing of data or averaging of collected data, the desired parameters for this are initialized. The appropriate frequency of the antenna receiver or transmitter being used is selected and a frequency range according to this is set. The number of data points for the measurement is set, as is the RF power level of both ports and the IF bandwidth. In addition, different trigger signal and source parameters are set. Further settings are initialized to allow for the S parameter measurements to be displayed on the vector network analyzer. In a separate embodiment, if using an oscilloscope and arbitrary waveform generator, the waveform to use as a signal for the arbitrary waveform generated is loaded. Various settings on the oscilloscope are initialized for the different channels such as the vertical scale, the horizontal scale, the bandwidth, the trigger level, the sample rate, and the record length. In addition, further settings are initialized to allow for the signal measurements to be displayed on the oscilloscope. Many of the settings from the previous initialization submodule <b>540</b> are hardcoded and not selectable or modifiable by the user in interface submodule <b>550</b>; however, if desired they can be altered and modified.

The interface submodule <b>550</b> provides an interface for a user to set up the conditions for the data to be collected and when these conditions are set to collect data. As a first step prior to data collection, it allows a user to set up initial positions via position calibration submodule <b>510</b>. The MW data and object detection data collections are performed separately and as such have separate conditions set. With the MW data collection, the conditions set up by the user may include, for example, the minimum and maximum rotation angle, the angular step, and the radial positions for both the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b>, the current frequency or frequency range of the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b>, the minimum and maximum vertical position of the object mount <b>70</b>, the vertical step, if any, the data file names and locations for storing the data files, if desired the number of times data at the same angular, radial, and vertical positions should be collected, and a signal loaded into an instrument. With the object surface position collection, the conditions set up by the user may include the minimum and maximum rotation angle and the angular step for the object surface position sensor <b>80</b>, the minimum and maximum position of the object mount <b>70</b>, the vertical step, the data file names and locations for storing the data files, and if desired the number of times data at the same angular, radial, and vertical positions should be collected. The interface submodule sets the conditions for the data to be collected by communicating with data file submodule <b>520</b>, rotation parameter submodule <b>530</b>, radial parameter submodule <b>580</b>, and vertical parameter submodule <b>590</b>. The interface submodule can call the previous initialization submodule <b>540</b> so that previously taken calibration data and/or instrument states is retrieved. The previously taking calibration data and/or instrument state that is retrieved is determined based upon conditions set up by the user in interface submodule <b>550</b>. The interface submodule further includes safeguards to ensure that the software is successfully communicating with necessary hardware and instruments. If a safeguard fails, the user will be prompted with an error message and given suggestions as to what caused the prompt. Once all the user conditions, initialization, and safeguards are passed the interface allows for an automatic way to collect either MW data via submodule <b>570</b> or object detection data via submodule <b>560</b>. In this sense the interface submodule <b>550</b> allows a user to perform all the necessary steps of the other submodules in the control module. In an embodiment, the interface submodule <b>550</b> communicates with necessary hardware and instruments (such as a vector network analyzer, oscilloscope and arbitrary waveform generator) using VISA (Virtual Instrument Software Architecture).

The object detection submodule <b>560</b> allows for the object surface position to be automatically collected once the conditions for collection are set in the interface submodule <b>550</b>. The collected data includes the distance from the object surface position sensor <b>80</b> to the object as a function of the angular position of object surface position sensor <b>80</b>, the z axis position of the object mount <b>70</b>, and if desired, a number to indicate how many times the data at the same angular and z-axis positions was collected.

The MW data collection submodule <b>570</b> allows for the MW data to be automatically collected once the conditions for collection are set in the interface submodule <b>550</b>. The collected data includes MW data representative of the MW scattered field as a function of the MW transmitter antenna <b>10</b> and the MW receiver antenna <b>20</b> angular and radial positions, the z-axis position of the object mount <b>70</b>, and if desired, a number to indicate how many times the data at the same angular and z-axis positions was collected.

The embodiments of the inventive concepts disclosed herein have been described in detail with particular reference to preferred embodiments thereof, but it will be understood by those skilled in the art that variations and modifications can be effected within the spirit and scope of the inventive concepts.

REFERENCE NUMERALS

<ul id="ul0001" list-style="none"><li id="ul0001-0001" num="0098"><b>10</b> MW transmitter antenna</li><li id="ul0001-0002" num="0099"><b>20</b> MW receiver antenna</li><li id="ul0001-0003" num="0100"><b>30</b> outer rotation unit</li><li id="ul0001-0004" num="0101"><b>40</b> inner rotation unit</li><li id="ul0001-0005" num="0102"><b>50</b> controller</li><li id="ul0001-0006" num="0103"><b>50</b><i>a </i>subcontroller</li><li id="ul0001-0007" num="0104"><b>50</b><i>b </i>subcontroller</li><li id="ul0001-0008" num="0105"><b>60</b> center axis</li><li id="ul0001-0009" num="0106"><b>70</b> object mount</li><li id="ul0001-0010" num="0107"><b>80</b> object surface position sensor</li><li id="ul0001-0011" num="0108"><b>82</b> sensing beam</li><li id="ul0001-0012" num="0109"><b>84</b> reflection beam</li><li id="ul0001-0013" num="0110"><b>86</b> radiation source</li><li id="ul0001-0014" num="0111"><b>88</b> photodetector</li><li id="ul0001-0015" num="0112"><b>90</b> computation processor</li><li id="ul0001-0016" num="0113"><b>95</b> database</li><li id="ul0001-0017" num="0114"><b>100</b> microwave imaging system</li><li id="ul0001-0018" num="0115"><b>202</b> support</li><li id="ul0001-0019" num="0116"><b>203</b> rotation surface mount</li><li id="ul0001-0020" num="0117"><b>206</b> outer ring support region</li><li id="ul0001-0021" num="0118"><b>204</b> inner ring support region</li><li id="ul0001-0022" num="0119"><b>207</b> support surface mount</li><li id="ul0001-0023" num="0120"><b>210</b> inner ring</li><li id="ul0001-0024" num="0121"><b>212</b> inner ring mount</li><li id="ul0001-0025" num="0122"><b>214</b> inner gear ring</li><li id="ul0001-0026" num="0123"><b>216</b> inner gear ring teeth</li><li id="ul0001-0027" num="0124"><b>218</b> spacer</li><li id="ul0001-0028" num="0125"><b>220</b> outer ring</li><li id="ul0001-0029" num="0126"><b>222</b> outer ring mount</li><li id="ul0001-0030" num="0127"><b>224</b> outer gear ring</li><li id="ul0001-0031" num="0128"><b>226</b> outer gear ring teeth</li><li id="ul0001-0032" num="0129"><b>230</b> pinion gear (inner ring)</li><li id="ul0001-0033" num="0130"><b>232</b> pinion gear (outer ring)</li><li id="ul0001-0034" num="0131"><b>236</b> stepper motor (inner ring)</li><li id="ul0001-0035" num="0132"><b>240</b> stepper motor (outer ring)</li><li id="ul0001-0036" num="0133"><b>238</b> drive shaft (inner ring)</li><li id="ul0001-0037" num="0134"><b>242</b> drive shaft (outer ring)</li><li id="ul0001-0038" num="0135"><b>246</b> z-axis actuator</li><li id="ul0001-0039" num="0136"><b>247</b> drive rod</li><li id="ul0001-0040" num="0137"><b>248</b>, <b>250</b> cables</li><li id="ul0001-0041" num="0138"><b>252</b>, <b>254</b> slip rings</li><li id="ul0001-0042" num="0139"><b>260</b>, <b>262</b> antenna mounts</li><li id="ul0001-0043" num="0140"><b>266</b> feedback monitor</li><li id="ul0001-0044" num="0141"><b>270</b> object position sensor mount</li><li id="ul0001-0045" num="0142"><b>274</b> lower mount</li><li id="ul0001-0046" num="0143"><b>278</b> radial translation unit</li><li id="ul0001-0047" num="0144"><b>282</b> translation stage</li><li id="ul0001-0048" num="0145"><b>286</b> gear</li><li id="ul0001-0049" num="0146"><b>290</b> motor</li></ul>